It can be mathematically demonstrated that heat supplied less heat discharged equals the maximum temperature less the minimum temperature in the cycle. In a theoretical Carnot engine cycle, differential heat energy is turned into power output by using working substances to transfer heat energy between a hot sink and a cold sink in a continuous loop. The continuous loop is an internal cycle, without external influence. In an actual Carnot engine cycle, the internal cycle is adversely effected by losses during heat transfer and conversion of heat energy into power output to perform work.